Oral mucosal stratified squamous epithelium (SSE) will be grown in traditional tissue culture and subcultivated onto defined, and increasingly complex, extracellular matrices composed of different collagen types and other macromolecules present in connective tissues and basement membranes. The influence that the various collagens and other extracellular macromolecules have on epithelial attachment, migration and growth will be determined using phase contrast microscopy and autoradiography. Oral epithelial cultures will also be grown at a liquid-gas interface--in a lifted configuration--on selected, defined extracellular matrices with the degree of SSE organization being assessed by the use of light and electron microscopy. Growth rate and the regulation of cell division as a function of differentiation will be studied by 3H-thymidine autoradiography. Potential cell surface differences between mitotically active, differentiating, and differentiated cells will be assessed by the use of labeled lectins having different specificities. The nature of cytoskeletal keratins and barrier lipids will be studied during the formation and differentiation of SSE in culture. Proteoglycan and glycosaminoglucan production by cultured SSE will be characterized as will the kinetics of basement membrane formation. The attachment, migration and differentiation of aberrant stratified squamous epithelium, the result of retinoic acid treatment, and malignant carcinomas arising from SSE will be assessed on the same defined extracellular matrices used for normal epithelium. The intent of these experiments is to determine if aberrant or malignant cells behave differently than normal cells on specific matrices, and, if so, whether those differences (--or in the case of an opposite effect, similarities) can be attributed to the composition of the matrix. Finally, defined extracellular matrices including basement membrane covered matrices will be used in wound healing studies to see if the matrices facilitate epithelial repair and regeneration. Relatively clean model systems such as those proposed in this application are useful in identifying factors that aid in oral epithelial wound healing as well as maintaining a functioning intact mucosal barrier. Such systems also have utility in the study of desquamative and hyperproliferative epithelial diseases and carcinomas.